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Compiled and presented by: Lynn Highland U.S. Geological Survey Golden, Colorado

Geographical Overview of the Three Gorges Dam and Reservoir, China – Geologic Hazards and Environmental Impacts. Compiled and presented by: Lynn Highland U.S. Geological Survey Golden, Colorado. Three Gorges Dam. Displacement Mass Movements Relocation. Dam Experimental Laboratory.

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Compiled and presented by: Lynn Highland U.S. Geological Survey Golden, Colorado

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  1. Geographical Overview of the Three Gorges Dam and Reservoir, China – Geologic Hazards and Environmental Impacts Compiled and presented by: Lynn Highland U.S. Geological Survey Golden, Colorado

  2. Three Gorges Dam Displacement Mass Movements Relocation

  3. Dam Experimental Laboratory China Three Gorges University (CTGU) was founded in Yichang City, in the year 2000, and is home to the construction of the Three Gorges Project. CTGU is a comprehensive university, which comprises the former University of Hydraulic & Electric Engineering and Hubei Sanxia University.

  4. 长江三峡大坝 (30.827° N 111.000° E) I I I 200 miles 400 km

  5. Chang Jiang (Yangtze River) “Long River” in Mandarin 662.4 km- (414 mile-) long reservoir The Yangtze begins in Tibetan highlands – flows to the East China Sea, and is 6,208 km (3,880 miles) long. It is one of the most sediment-filled rivers on earth.

  6. 111.000° E I 30.827° N --- Dam Reservoir will be 662 km (414 miles) long after final filling in 2009

  7. 414 miles A 662km-(414-mile) long reservoir in the United States

  8. Three Gorges Dam Facts Dam type: Concrete Gravity Dam height: 199m (652 feet) Dam length: 2.24 km (1.4 miles) Expected investment: 203.9 billion yuan (U.S. $24.6 billion) Construction period: 1993-2009 People to be displaced: 1.3 to 1.9 million Area to be submerged: 1,000 sq km (400 square miles ) Dam Reservoir length: 662 km (14 miles ) Storage: 39.3 billion cubic meters of water (51.4 billion cubic yards). The Three Gorges Dam will produce 50 percent more power than South America's Itaipu Dam, which used to be the largest dam in the world.

  9. Three Gorges Dam: 1. Will improve flood control 2. Will improve ship navigation as areas of rapids will disappear and the treacherous twists and turns of navigating the Gorge will be moderated 3. Will provide more, and less-polluting hydro-electric energy, as China currently produces 75 - 80 % of its power through coal-burning. The Three Gorges Hydropower Plant (TGHP) contains twenty-six turbine-generator units, each with installed capacity of 700MW, not including the six more 700MW units in the Right Bank Underground Powerhouse under construction. AThree Gorges Project estimation is that it will save 50 million tons of coal yearly .

  10. Reservoir filling and water level rise in controlled stages. Structural completion of Dam, May 2006 • Began filling reservoir, June 2003, while dam was still under construction; water level was raised to 135 Meters (443 feet) • 2nd filling began September, 2006, raising reservoir level to 468 feet (143 m) by late October. 3. Complete water level height in 2009 – 175 meters (575 feet)

  11. A mountain was literally leveled to make way for the locks Ship Locks for ship navigation through the dam. Currently takes a ship 4 hours to go through the 5 locks. Eventually, a yet- to-be-built hydraulic lift will lift the ships through much faster Photos from official Three Gorges Dam website: http://www.ctgpc.com/

  12. As the river level slowly floods the gorges, about 1.16 million people have been relocated since construction began in 1993. Some people have been moved to higher elevations above the river, others to other parts of China

  13. Three Gorges Dam Visitor Center, Yichang City, China

  14. Satellite Images of the Three Gorges Dam EAST Aerial photo above, shows reservoir at 135 m (443 feet) high in 2006-- it will be 175 m (574 feet) in 2009.

  15. The 600+ km (414-mile) long reservoir will inundate some 1,300 archeological sites and alter the landscape of the Three Gorges area.

  16. A Short HISTORY 1. In 1918, Sun Yat-Sen suggested, in his book Strategy for State, Part II: Industrial Plans, a scheme to “improve the upstream from here”, that is, “a dam should be set here to let ships go downstream and use the water resource as power.” 2. In May 1945, Dr. John Lucian Savage, a famous American expert in dam construction put forward his Preliminary Report on Development Plans of Three Gorges. After many, many state councils, and a preliminary small dam was constructed, it was decided the 3 Gorges Dam Construction should go ahead 3. On 14 Dec 1994, the Three Gorges project was officially started. A series of 5 locks to facilitate ship navigation was also started. 4. On 16 June 2003, the trial navigation of ship locks succeeded. On 18 June 2003, the ship lock started to be open to all sorts of ships. 5. On 10 July 2003, the first generator unit began generating and was connected to the power grid. 6. September, 2006 – secondary filling of reservoir begins – to finish late October

  17. Temporary Coffer dam In June, 2006, the temporary cofferdam, which was used to block water while the main body of the new dam was constructed, was destroyedbya13-second blast of 191 tons (173,000 kg) of explosives, enough to topple 400 10-story buildings

  18. Site Selection, 1959 A C D B 2nd Phase Nov. 1997 - 2003 1 1st Phase 1993 - Nov.1997 A 2 3 3rd Phase 2003-2009 A B 4 Completion: In 2009

  19. 175 Meter height (574 feet) - 2009

  20. Yangtze River Before 2003 filling Yangtze River Current water depth Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite view (Photo by NASA)

  21. Future River Level – 2009 175 m On the river banks, 175-meter markers are placed at regular intervals along the river 175 M (574ft.) in 2009

  22. 2006 175 m 2007 175 m 135 m 2003 Dragon’s Gate Bridge (The Gate of Little Three Gorges) – rising water level 135 m Original river level

  23. Relocation Housing Built by the Government Anticipated water level in 2009 River

  24. Original housing remains intact – not demolished since it is located above the 2009 final fill level of the Yangtze River

  25. Town of Shazhenxi (16 miles upstream From the dam)

  26. Some of the Geologic Hazards in the Three Gorges Area: Landslides and Other Slope Failures Destructive Waves in the River from Slope Failures Earthquakes and Reservoir-Induced Earthquakes Sediment Problems

  27. ►The Three Gorges have been formed by severe incision along narrow fault zones, in response to Quaternary uplift, of massive limestone mountains. These mountains are lower Paleozoic and Mesozoic age. Geology & Rainfall ►Steep slopes develop on easily erodible or “soft” materials, which are extensive, and landslides are common in these areas. ►Rainfall - The average winter precipitation, in this part of China, is 100–150 mm (4 - 6 inches) per month, and the spring–summer (March – August) average can be as high as 200–300 mm (7 – 11 inches) per month.

  28. Slope Failures in the Three Gorges Area 1. Rotational slumps in poorly consolidated or unconsolidated materials. 2. Translational rock and debris slides, debris flows and complex slides involving more than one type of failure mechanism and several types of material. 3. Geomorphologic characteristics influencing slope instability in the study area are the attitude of strata with respect to slope angle and aspect. Areas where strata dip towards the slope face tend to experience translational slope failures and slumps, such as rock creeping and landsliding. 4. Massive urban development required for the relocation of major towns to nearby higher positions has triggered several large landslides. 5. Raising and lowering the water level in the Dam reservoir for flood control will saturate older and still-active landslides and subject them to extreme wet-dry cycles – rainfall will intensify the effect.

  29. Jet-boat on Yangtze River – will go about 45 mph

  30. Landslides Observed on Three Gorges Field Trip July/August 2006 Xintan landslide – on a bank of the Yangtze River, 16 miles (26 km) upstream from dam Lianziya Dangerous Cliff – Crag Mass – on opposite bank from the Xintan landslide Shuping landslide – on a bank of the Yangtze 49 km upstream from dam Qianjiangping landslide – On the Quing’ganhe River, a tributary of the Yangtze At least 14 old landslides are considered likely to be reactivated by the filling of the reservoir.

  31. Xintan Landslide June 12, 1985, destroyed Xintan Town in Hubei Province, located 26 km (16 miles) upstream from the Dam-- The landslide body slid into Yangtze River, a third of river width was blocked, and the resultant wave reached 54 m (177 feet) in height and propagated along the river for 42 km (26 miles), 9 people were killed and 77 boats destroyed. People had been evacuated before the slide. 2009 fill level The landslide caused a two-day interruption in shipping on the Yangtze

  32. The 1985 Xintan Landslide – The photo was taken right after failure

  33. Lianziya Rock Mass Xintan Landslide Yangtze River

  34. Lianziya Rock Mass – across the river from Xintan Landslide There are 6 crag masses in the reservoir area-- the most dangerous is Lianziya crag near Military Books and Precious Sword Gorge. The China Ministry of Geology and Mineral Resources monitor these sites.

  35. Lianziya is composed of limestone and thin shale and lies on a soft coal layer with varying thickness of 1.6 - 4.2 m (approx. 5 - 14 feet). The coal layer was mined out, and slope deformation has taken place in recent years. For the past twenty years measures to control this hazardous situation have been tried. It is continuously being monitored (photo by Lang Yu-Hua). Stabilization works

  36. Lianziya rock fall “dams”

  37. Installing Corner Reflectors for InSAR data in order to measure deformation at the Xintan Landslide and Lianziya Rock Mass A corner Reflector being installed At Lianziya Rock Mass (Photos from Xia, et al, 2004) For Xintan Landslide

  38. Close-up Photo of a Corner reflector

  39. InSAR topography of Yangtze River/Three Gorges Area

  40. One month after the June 2003 filling of the reservoir, the old landslide began deforming, with cracks on the mass growing ever wider. The deformation is still developing today. Geologists at Kyoto University, Japan, are monitoring this slide and are working to install some type of improved warning system – at present, the basic warning “system” is a flashing yellow strobe light that activates when the landslide moves. In 2004 most inhabitants were permanently moved off the slope (photo by China Geological Survey, Yichang City Branch).

  41. The Qianjiangping landslide occurred in July, 2003. It is located on the Qing’ganhe River (a tributary of the Yangtze River), 3 km (1.8 miles) from the confluence. Stability of the affected slope was already reduced by a previous landslide at the site, pre-existing bedding-plane shears, quarrying of mudstone from the landslide toe, and heavy rain. 26.5 km (16 miles) from the dam

  42. Important Aspects of the Qianjiangping Landslide of July 13, 2003 --Location: the Qianjiangping Landslide is in Hubei Province, on the Quing’ganhe River, a tributary of the Yangtze. The landslide is 24 million cubic meters (31,390,814 million cubic yards) in volume. --The landslide lasted for about four hours from slight precursors to the final avalanche. --Four factories were destroyed and 129 families lost their homes. A total of 252 people and 67 households moved out of the affected area of the landslide. --Because of the local monitoring system and early warning, most people evacuated safely in time. Officially, 14 people were killed, 10 listed as missing. --Officials in Hubei Province decided heavy rains caused the failure, but subsequent investigation has concluded that it was probably due to several factors—including heavy rainfall, and the raising of the water level in the tributary. This landslide was also a re-activation of an old landslide.

  43. Small landslide on banks of Yangtze near the dam – this section will be under water by 2009

  44. What else is being done to mitigate the effects of landslides?

  45. Strengthening river banks with concrete, in anticipation of the rising water level (Badong is located on an old landslide)

  46. Another view of riverbank strengthening - Badong

  47. What is the Earthquake Hazard to the Three Gorges Dam Area?

  48. The Three Gorges project authority conducted an extensive survey, and found that the dam is situated near six fault lines. • 2. The Jiuwanxi Fault is located just 17 kilometers (10.5 miles) upstream. • The Zigui-Badong fault, 80 km (50 miles) upstream from • the dam - is considered likely to produce earthquakes that could have an impact on the dam site. The Zigui-Badong fault was responsible for a M = 3. after the reservoir began filling in 2003 (There had had been a M = 6 in the past). • Three Gorges Dam is built to withstand a M = 7.0 earthquake

  49. Earthquakes and Earthquake Monitoring in the Three Gorges area A network of 21 digital earthquake monitoring stations is to be set up in the Chongqing section of the Three Gorges Reservoir (far western end of the reservoir) area by the end of 2007 Costing 29.6 million yuan (3.7 million U.S. dollars), the stations will monitor seismological activity around the clock and provide an earthquake warning system for the local government

  50. Sample of Historical Seismicity in the Three Gorges Area: From 1407 to 1631, four medium and strong earthquakes were recorded, with the largest believed to have been magnitude 6.5. From 1855 to the present, six medium and strong earthquakes have been recorded, the biggest having a magnitude of 5.5. Recurrence Rates: 4 or 5 earthquakes occurred every eight to 10 years in the Three Gorges area.

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